A contrast-enhanced CMR-based risk score integrating microvascular obstruction and intramyocardial hemorrhage extent for prognostic evaluation

OBJECTIVES: This study aims to compare the prognostic value of the extent of microvascular obstruction (MVO) combined with intramyocardial hemorrhage (IMH) for major adverse cardiovascular events (MACE) in patients with STEMI. MATERIALS AND METHODS: We analyzed 568 STEMI patients in this retrospective multicenter study. Microvascular injury was visualized using late gadolinium enhancement for MVO, and T2* mapping and T2-weighted cardiovascular magnetic resonance imaging for IMH. The Youden index was used as the cutoff value to divide the study population into four groups. The Eitel CMR risk score, Glasgow CMR risk score, and GRACE (Global Registry of Acute Coronary Events) score were used as references to form Scores 1 and 2. Score 3 included LVEF ≤ 45%, MVO > 1.06% LV, IMH > 0.47% LV, and the GRACE score. RESULTS: During a median follow-up of 3.1 years (IQR: 1.7-5.0 years), 108 patients (19%) experienced MACE. Event rates increased stepwise across groups (8.8% to 58.3%). The combination of MVO > 1.06% LV and IMH > 0.47% LV emerged as the strongest predictor of MACE (HR: 9.646, 95% CI: 6.327-14.705 [p < 0.001]). Score 3 (integrating GRACE score, LVEF, and quantitative MVO and IMH) demonstrated improved predictive performance for MACE compared to the GRACE score (AUC: 0.748), Score 1 (AUC: 0.825), and Score 2 (AUC: 0.802), achieving an AUC of 0.853. CONCLUSION: Our approach integrates quantitative information on MVO and IMH into a risk score that shows better prognostic value than established risk scores. KEY POINTS: Question Current prognostic tools for ST-elevation myocardial infarction patients lack quantitative combined assessment of microvascular obstruction and intramyocardial hemorrhage, limiting precise risk stratification after reperfusion. Findings A novel cardiac magnetic resonance score integrating quantitative microvascular obstruction and intramyocardial hemorrhage extent achieved 0.853 area under the curve for major adverse cardiovascular events. Critical Relevance Statement This study develops a quantitative cardiac magnetic resonance risk score by integrating microvascular obstruction and intramyocardial hemorrhage, offering improved prognostic value for major adverse cardiovascular events in ST-elevation myocardial infarction patients over established clinical scores.